<template>
  <div class='xtx-carousel' @mouseenter="stop()" @mouseleave="start()">
    <ul class="carousel-body">
      <li class="carousel-item"  v-for="(item,i) in sliders" :key="item.id" :class="{fade:index===i}">
        <RouterLink v-if="item.imgUrl" to="/">
          <img :src="item.imgUrl" alt="">
        </RouterLink>
        <!-- 轮播商品 -->
        <div v-else class="slider">
          <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
            <img :src="goods.picture" alt="">
            <p class="name ellipsis">{{goods.name}}</p>
            <p class="price">&yen;{{goods.price}}</p>
          </RouterLink>
        </div>
      </li>
    </ul>
    <a @click="toggle(-1)" href="javascript:;" class="carousel-btn prev"><i class="iconfont icon-angle-left"></i></a>
    <a @click="toggle(1)" href="javascript:;" class="carousel-btn next"><i class="iconfont icon-angle-right"></i></a>
    <div class="carousel-indicator">
      <span v-for="(item,i) in sliders" :key="i" :class="{active:index===i}"></span>
    </div>
  </div>
</template>

<script>
import { onUnmounted, ref,watch } from 'vue'

export default {
  name: 'XtxCarousel',
  props:{
      sliders:{
        type:Array,
        default:()=>[]
      },
      duration: {
        type: Number,
        default: 3000
    },
      autoPlay: {
        type: Boolean,
        default: false
    }
  },
  setup(props){
    let index =ref(0)
    let timer=null
    //1.自动播放
    const autoPlay=()=>{
        clearInterval(timer)
        timer=setInterval(()=>{
            index.value++
            if(index.value >= props.sliders.length){
                index.value=0
            }
        },props.duration)
    }

    watch(()=>props.sliders,(newVal)=>{
        // 判断：当slider有数据且是auto时 自动播放
        if(newVal.length && props.autoPlay){
            index.value = 0
            autoPlay();
        }
    },{immediate:true})

    //2.鼠标进入离开，暂停，开启
    const stop=()=>{
       if(timer) clearInterval(timer)
    }
     const start=()=>{
         // 判断：当slider有数据且是auto时 自动播放
       if(props.sliders.length && props.autoPlay){
           autoPlay();
       }
    }
    //3.指示器切换，上一张，下一张,圆点切换
    const toggle=(step)=>{
        let newIndex=index.value+step
        //判断 超出范围
        if(newIndex>=props.sliders.length){
            index.value=0
            return 
        }
        if(newIndex<0){
            index.value=props.sliders.length-1
            return 
        }

        //正常
        index.value=newIndex
    }

    //4.销毁组件，清理定时器 
    onUnmounted(()=>{
        setInterval(timer)
    })

      return {index,stop,start,toggle}
  }
}
</script>
<style scoped lang="less">
.xtx-carousel{
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel{
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0,0,0,0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background:  #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0,0,0,.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev{
        left: 20px;
      }
      &.next{
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
// 轮播商品
.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px!important;
      height: 230px!important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
</style>